Add browser_evaluate tool for JavaScript execution#60
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hugs merged 7 commits intoVibiumDev:mainfrom Feb 8, 2026
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Add --disable-notifications flag and set notifications content setting to block, preventing the "Google Chrome for Testing Notifications" dialog from appearing on first launch. Co-Authored-By: Claude Opus 4.5 <[email protected]>
This adds a new MCP tool `browser_evaluate` that allows executing JavaScript code in the browser and returning the result. Changes: - Add browser_evaluate tool schema in mcp/schema.go - Implement browserEvaluate handler in mcp/handlers.go - Update tests to expect 8 tools instead of 7 - Add test for browser_evaluate functionality The tool uses the existing Evaluate() method from the BiDi client, making this a small addition that exposes existing functionality. Use case: Extract HTML content from page elements, inspect DOM state, or run custom JavaScript for automation tasks. Co-Authored-By: Claude Sonnet 4.5 <[email protected]>
Makes it clear that browser_evaluate is the primary tool for extracting data from pages, not just executing arbitrary JavaScript. Co-Authored-By: Claude Sonnet 4.5 <[email protected]>
Update MCP tools documentation to include the browser_evaluate tool added in PR VibiumDev#60. This tool executes JavaScript in the browser to extract data, query the DOM, or inspect page state. Co-Authored-By: Claude Sonnet 4.5 <[email protected]>
Implement feature parity with JavaScript client and MCP server by adding evaluate() method to execute JavaScript in the page context. Changes: - Add async evaluate() method to Vibe class - Add sync evaluate() method to VibeSync class - Add comprehensive tests for string, numeric, and object evaluations - Use script.evaluate BiDi protocol method All Python client tests pass. Co-Authored-By: Claude Sonnet 4.5 <[email protected]>
Add browser_evaluate to MCP tools table and showcase the new evaluate() method in all client examples (JavaScript and Python, both sync and async). Changes: - Add browser_evaluate to MCP server tools table - Add evaluate() examples to JS sync and async code samples - Add evaluate() examples to Python sync and async code samples Co-Authored-By: Claude Sonnet 4.5 <[email protected]>
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merged. thank you, @jolks! |
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Summary
This PR adds a new MCP tool
browser_evaluatethat allows executing JavaScript code in the browser and returning the result. Also addsevaluate()method to the Python client for feature parity with the JavaScript client.Changes
MCP Server (Go):
browser_evaluatetool schema inmcp/schema.gobrowserEvaluatehandler inmcp/handlers.gobrowser_evaluatefunctionalityPython Client:
evaluate()method toVibeclass (async API)evaluate()method toVibeSyncclass (sync API)JavaScript Client:
evaluate()method already exists (clients/javascript/src/vibe.ts:68-82)Implementation
The MCP tool uses the existing
Evaluate()method from the BiDi client, making this a small addition (~50 lines) that exposes existing functionality.The Python client implementation mirrors the JavaScript client's
evaluate()method, using thescript.evaluateBiDi protocol method.Context
The underlying Go BiDi client has always had an
Evaluate()method, and the JavaScript client has hadevaluate()since its initial implementation. This PR:browser_evaluatetoolevaluate()method to the Python client for feature parityUse Cases
document.querySelector('#container').outerHTML)document.title,window.location.href)Testing
MCP Server Tests:
Python Client Tests:
document.title)2 + 2)window.location.href)make test-python # Python client test passed!Feature Parity
All three interfaces now support JavaScript evaluation:
browser_evaluatetool) - NEWvibe.evaluate()method) - already existedvibe.evaluate()method) - NEWRelated
This enables use cases like extracting structured data from web pages without relying solely on CSS selectors, which was the motivation for this addition.